Reasoning About a Classification of Crosscutting Concerns in Object-Oriented Systems

and behavior of crosscutting concerns in OO systems. We further argue that aspects must be defined as first-class abstractions in order to be manipulated as such and thus to provide for reusability and dynamic adaptability as well as for the creation of dynamically loadable aspect repositories

Functions and Traversals in Combination

In this paper we describe a new traversal organization inspired by ideas behind type-generic traversals that clearly separates traversal code and computation, implemented in an object-oriented setting. By delegating portions of the traversal and computation to separate functions we provide a library and methodology to develop succinct solutions to data-structure transformation problems. Because we provide an implementation of these new traversals via reflection in Java, all previous tools and libraries are still available and functionality can be extended and composed to deal with data structure reorganization using inheritance and encapsulation. We demonstrate the use of these abstractions by solving a few prototypical language problems: calculation of de Bruijn indices and type-checking